Home transmission flush success

douchbaggery

Member
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Mazda CX-9
Thanks, but you left most of the old fluid still in there with that method. I'm going to let it run out of the coolant line and get as much of the old fluid out as possible.

You won't regret it. Its honestly super easy and very gratifying knowing you're getting all the old fluid out except maybe a few tablespoon fulls. My fluid looks perfect even after 30k miles on the new synthetic fluid I put in it. (but I changed it anyway) And that's on my old 08 model with 168,000 miles on it. I also added a bypass filter (also pretty easy to do) from the line you pump the fluid out of, so now I have some real filtration on the tranny too. I did this on both our CX9's.
 
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2007 Mazda CX-9 Touring
Pootie tang is your car a front drive. I was trying to look for the same set up on my awd and it doesn't look the same as in the picture. Has anyone here with awd used the flush method with the return line. Hopefully I can get some input here. I will check again in a couple of weeks to see if I can find the return line. I was able to do this on my sons fusion. Once you get the line out everything else should be easy.
 

damaster

Zoom Zoomin'
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2011 CX-9 GT
Mine is a 2011 AWD, no dipstick. I used 15L of Valvoline MaxLife ATF (suitable for Toyota T-IV). Here's how I drained and flushed my transmission fluid (mostly followed douchbaggery's post above):

  1. Remove the air box. This is fairly simple as there are only three 10mm bolts to remove and a clamp to loosen as pictured below. Then you just pull the whole air box upwards and out.
    cx9_tf_0.jpg
  2. You should now be able to see the T55 torx filler bolt pictured below. Loosen that and take it out. Mine was on fairly tight so I had to use a breaker bar with a very long socket extension to loosen it. Note this picture also shows the flow of transmission fluid out of the hose going to the radiator which you'll need to remove in step 8.
    cx9_tf_1.jpg
  3. Jack up the car.
  4. Underneath the transmission there's a T40 torx drain plug that is set inside a 17mm level tube bolt. First loosen and remove the T40 drain plug to let most of the old fluid out. When fluid stops flowing out of there, loosen and remove the 17mm level tube bolt and let more of the old fluid drain out. Notice how dark brown the old fluid is.
  5. Measure how much you took out. Mine was approximately 3.2L.
  6. Put the 17mm leveling tube and T40 drain plug back on. Tighten the 17mm to approximately 30 ft-lbs.
  7. Pour new fluid in via the top fill hole, the same amount as the old fluid that came out, so in my case that was 3.2L.
  8. Unhook the transmission fluid hose that goes in to the radiator shown in the picture for step 2. This is fairly easy to remove from the top so no need to try to do it from underneath the car.
  9. Connect a 3/8" hose to the hard end coming out of the transmission and put it into a bottle with measurements marked on the bottle. I used an empty Costco-sized Windex bottle and marked it off at 1L increments (just used water to figure out the increments and a sharpie to make the lines based on the water level). Here's a picture from the top with the radiator hose removed and my 3/8" hose connected and feeding into the Windex bottle and also a picture from underneath of my nifty Windex bottle:
    cx9_tf_2.jpg


    cx9_tf_3.jpg
  10. This next step is much easier if you have someone else sit in the driver's seat. Start the engine and watch the old fluid pour out of the hose and into the bottle. Shut off the engine just before it gets to 2L in the bottle. Pour the same amount of new fluid back in through the top fill hole. Repeat this process about 4-5 times or until the fluid coming out of the hose is new (red instead of dark brown). During one of these flushing iterations move the shifter out of P and into R and D and R and D and back into P.
  11. Replace the T55 upper fill plug and tighten to approximately 30 ft-lb.
  12. Replace the air box.
  13. Drive the car until the transmission fluid temperature is between 34-47 C. I used an ELM327 bluetooth OBD adapter and Torque Pro on Android with a custom PID to get a transmission fluid temperature reading
  14. Leave the engine running and remove the T40 torx drain plug underneath the transmission. If fluid flows out, allow it to stop flowing. When it stops it's at the right level. If very little or nothing comes out then add more new fluid in from the top fill hole slowly until it starts pouring out from the drain plug underneath. When it stops flowing out of the drain plug the level is right. It's important to do this at the right TFT of 34-47 C; if not the level will be too high or too low. Note that removing the air box while the engine is running may throw a CEL and cause the engine to stall out; my solution to this was to keep the lid of the air box (which contains the MAF) connected to the intake pipe (the part where you loosened the clamp).

I'm very happy with the results. I have about 5 years of driving but only 85000 km on the CX-9 and yet the transmission was really rough lately, especially during downshifts and worse during warmer weather; i.e. very jerky. After the TF flush it's smooth like new again.
 
AWESOME write-up and pics! Thank you! One question, why didn't you flush out from the return of the trans oil cooler to your bottle?
 

telange

Member
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2013 Mazda CX-9 Touring AWD
Pootie tang is your car a front drive. I was trying to look for the same set up on my awd and it doesn't look the same as in the picture. Has anyone here with awd used the flush method with the return line. Hopefully I can get some input here. I will check again in a couple of weeks to see if I can find the return line. I was able to do this on my sons fusion. Once you get the line out everything else should be easy.

I've used this method on my 2013 Touring AWD; using the photo posted by Pootie Tang and foradrive as a reference. At the bottom of radiator, on the passenger side, is the return line TO the transmission. Loosen and remove the end of this hose attached to the metal tubing on the transmission. This is the discharge point while flushing.
 
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2007 Mazda CX-9 Touring
Thank you for all of the replies. I will look at this again with a copy of the pic nearby. Another question which fluid in everyones opinion would be better to use? the Toyota T-IV or The mobil 3309. For those who use the mobil 3309 what is your experience as far as how the trans operates also to the people who use the T-IV how is that working. Once again thank you all for the input. Very helpful I really appreciate it.
 

damaster

Zoom Zoomin'
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2011 CX-9 GT
AWESOME write-up and pics! Thank you! One question, why didn't you flush out from the return of the trans oil cooler to your bottle?

I actually tried that first. There are 2 hoses coming out of the cooler, one thinner than the other. I removed the thinner one and attached my 3/8" tubing to the hard metal end. Unfortunately, the fluid flow was in the wrong direction and instead of coming out of my tube it came out of the radiator line and made a mess on my garage floor. The radiator line wasn't long enough to just pour directly into a bottle, nor was I able to fit any tubing I had at home to it. So for me it was a lot easier to just remove the line in my picture from the top and connect my 3/8" tube directly to that.
 
Ah, gotcha. I used a barbed hose connector and hooked it up. Oh, and I used a 6-foot length of hose so the drain bottle could be out from under the car and I could see it from the driver's seat. Just sharing tips!
 
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2007 Mazda CX-9 FWD Sport
Thanks for the DIY! I bought a case of 12 Mobil 1 3309 (identical to Toyota T-IV) from amazon for $70 and did my flush on a 2007 FWD with all 12 bottles. Easy peasy with your write up.
 
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2007 Mazda CX-9 Touring
Pootie tang, I really hate to ask this question as this thread is kind of old. The pic of the return line is that looking down from the top of the car? I was looking for that beige piece in the pic as a reference when I had the car jacked up and secured and could not see it and I started wondering if this is looking down from when the hood is opened.
 
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Mazda CX-9 Grand Touring 2016
3309 is the Aisin (transmission maker) spec. T-IV is Toyota's name for the same fluid.

I like to drain the transmission sump first, and refill, to save some time, then pump through the hose.

If which hose is the discharge to the cooler is in question, take one loose and crank (don't run) the engine. You'll see the direction of the flow and know which hose is which.

Installing a Magnefine or Filtran filter is always a good idea. Every hydraulic system needs clean fluid, including automatic transmissions. Put in the hot line into the cooler for best filtration. (After a transmission failure bits of metal accumulate in the cooler, so the filter is put on the cooler outlet in that case.) It is also a very good idea to put a similar filter in the return line of the hydraulic power steering. Magnefine's 1/2" filter works well for this. These filters are often re-labeled as NAPA or WIX or something else. All good.
https://magnefinefilters.com/main.sc
 

flash25296

Member
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2014 Mazda CX-9
To do a fluid exchange at the two Mazda dealers in my area its $219 -$229. Both indicated a fluid exchange is done and 12 quarts are used in the process. My mileage is now 59,980 so figured it might be a good time to do the fluid change. I thought about doing the 3.5 qrts multiple times method but was wondering if the full fluid exchange is a better path for transmission longevity?
 

flash25296

Member
:
2014 Mazda CX-9
To do a fluid exchange at the two Mazda dealers in my area its $219 -$229. Both indicated a fluid exchange is done and 12 quarts are used in the process. My mileage is now 59,980 so figured it might be a good time to do the fluid change. I thought about doing the 3.5 qrts multiple times method but was wondering if the full fluid exchange is a better path for transmission longevity?

I took my CX-9 to Herzog-Meier Dealership in Beaverton, Oregon and they Charged $199.95 for a complete fluid swap on the transmission. They even saved me a sample of the fluid that came our of the transmission and it did not look all that bad at 60080 miles.